The trial had prompted global outrage, with rights groups saying it showed that Mr Dos Santos' government was becoming increasingly repressive in its attempts to remain in power.

Human Rights Watch said the verdict was "a ridiculous scandal", while Amnesty International described the defendants on Twitter as "prisoners of conscience" who had been subjected to a "kangaroo court trial [which] violated international standards".

Prosecutors defended the arrests, arguing that the 17 were planning an uprising among students and workers "with incalculable consequences".

The jailed activists, who belonged to a youth movement, had previously held demonstrations demanding the resignation of Mr dos Santos, who has been in power for 36 years.

Their book club had discussed the 1993 book by Gene Sharp called From Dictatorship to Democracy: A Conceptual Framework for Liberation.

Angola is Africa's second-largest oil producer, and has witnessed an economic boom since the end of a civil war in 2002.

However, critics of the elected government say the wealth has only benefited a small elite.

Who is Gene Sharp?

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Gene Sharp is a US academic who researches non-violent revolution.

He is credited with the strategy which led to the toppling of Egypt's long-time leader Hosni Mubarak in 2011.

His most translated and distributed work, From Dictatorship to Democracy, was written for the Burmese democratic movement in 1993, after the imprisonment of Aung San Suu Kyi.